Green’s Dictionary of Slang

sweetener n.2

1. [early 19C+] a gratuity; a bribe.

2. an encouragement.

3. [mid-19C] (US) a drink.

4. [mid-19C] a hard blow.

5. a scolding, a ‘talking-to’.

6. [late 19C] (UK Und.) in pl., the lips.

7. [1900s] the penis.